A man has been jailed for 39 months for sending messages from his BlackBerry telling people to join in last August's riots in Nottingham.

Sam Lowe, 21, from Nottingham, had admitted a charge of encouraging violent disorder after he sent a BlackBerry Messenger instant message, or BBM, telling his 160 contacts to "kick off" during disorder in the city in 2011.

Nottinghamshire police said the message, which Lowe later deleted, read: "Girls, grannies, mums, dads, lads, grandads – everyone meet on Sneinton Dale tonight at 9 o'clock as we are all going to kick off…"

The message also urged his friends to show the police "what it's all about".

More than 141 people were arrested and 87 were charged after cars, pubs and shops were damaged in August 2011 in Nottingham. However, the court heard there was no evidence that Lowe's message had led to public disorder in the area.

He was arrested in the early hours of 9 August after he had hidden from police in bushes for two hours. Further examination of Lowe's phone messages found he had claimed to have "a bin full of bricks".

The judge acknowledged Lowe had previously done a lot of good in his community and had been given a "volunteer of the year" award.

However, he told Lowe: "What you did, potentially, you took a large amount away from your community."

But the sentence has caused consternation among rights organisations. Jodie Blackstock, director of criminal and EU justice policy at Justice, said: "We don't think that this is the right approach – a harsher sentence isn't going to achieve what they [the courts] are looking for. In a case like this, a high level community sentence would be appropriate. Considering nothing occurred, and arguably it was carried out in the heat of the moment without any intention – 39 months is a huge leap."

David Cameron has previously defended the sentences handed out to those involved in the riots, and said: "They've decided to send a tough message and it's very good that the courts feel able to do that."

Rich Henson, a detective with Nottinghamshire Police said: "BBM is not your standard mobile communication. It is much more secure. The fact that BBMs have advanced security and encryption means they are almost impossible to access by third parties.

"That is why Lowe's conviction is a particularly great result for the force, demonstrating some first-class work by our digital investigation unit."

He added: "Let this be a clear warning to those criminals out there who think they are safe using BlackBerrys."

Detective chief inspector Rob Griffin, who is leading the investigation into the August disorder in the city, said: "The judge today has handed down a sentence to reflect the seriousness of Lowe's actions. It is impossible to quantify the impact and effects of the messages he sent that night.

"It is clear, however, that this was an irresponsible and criminal act at a time when people were rising up against the police on a national scale."